Lissen

And I remember in my youth, in the Lisne of a Rock at Kingſcote in Gloceſtershire, I found at least a Bushel of Petrified Cockles actually distinct one from another, each near as big as my Fist.

Beside these, we have another fine Earth, of a white co­lour, porous and friable, insipid and without scent, dissoluble in water; and tinging it, of a milky colour, and somtimes raising a kind of ebullition in it; found frequently in the lissoms or seams of the Rocks, or sticking to the hollow roofs of them: in short, so altogether agreeable to what Conradus Gesner calls Lac Lunae, that I could not but think it the very same.

Lissen, mate... You'll run into all sorts o' trouble if you don't keep your eyes peeled.